Plasterboard



E. E. HARPER June 14, 1938,

PLASTERBOARD Filed Sept. 21, 1-957 1 NvENToQ; EDGHR ERNESTHHRPER Patented June 14, 1938 PATENT OFFICE PLASTERBOARD Edgar Ernest Harper, London, England, assignor to Hessolite, Limited, London, England, a British company Application September 21, 1937, Serial No. 164,845 In Great Britain May 21, 1936 2 Claims.

This invention relates to wall boards or slabs for building purposes especially to wall boards of the kind composed primarily of a gypsum plaster and utilized generally for covering ceiling joists or wall studding and upon which a surface flnishing coat of plaster is applied after the wall boards have been erected.

Wall boards now generally in use comprise a sandwich of gypsum plaster or other substances between two layers of paper or cardboard which present a comparatively smooth surface on both sides of the board, the edges of which are square. In the fixing of such boards the edges thereof are butted together, the boards nailed to the joists or other foundation and the joints and nail heads covered with a strip of scrim which is glued or otherwise secured in position. A plaster finishing coat is then applied to provide the finished wall or like surface. Difficulties arise, however,

in applying such finishing surface in that the is to obviate such a disadvantage and further to provide a wall board which may be more satisfactorily bonded 'with the next adjacent wall boards when applied to joists or other founda- I tion.

According to the invention awall board comprises a base of corrugated material, for example, corrugated paper, an intermediate layer of plaster, for example plaster of Paris or like gypsum base material and a fabric covering for example Hessian, for said plaster layer, the said fabric being extended at two meeting sides which, when the board is in use, can be so arranged as to overlap the joint formed with the next adjacent board or boards and provide a bond therewith when a finishing coat of plaster is applied.

The corrugated paper is preferably of the kind extensively used for packing purposes and consisting of a corrugated sheet of paper to one side of which is attached a fiat sheet of paper by an adhesive.

In order that the invention may be clearly understood reference is directed to the accompanying drawing wherein:

Fig. 1 is a perspective view of wall board constructed in accordance with the invention;

Fig. 2 is a perspective view showing a number of wall boards in position to form a surface for plastering.

Referring more particularly to Fig. 1, a wall board comprises a backing or base A of corrugated paper or cardboard to which is applied an intermediate layer B of plaster of Paris. A layer of scrim, or other woven fabric C is applied to the plaster base prior to the setting thereof and in such a manner that the fabric is intimately associated with the plaster and provides a key to which a finishing coat of plaster may be applied when the boards have been erected. It has been discovered that a coarse type of canvas known as Hessian is the most suitable for effecting the object of the invention as the loose short fibres of the weft and warp form a key with the plaster not only of the intermediate layer but with the subsequently applied finishing coat.

The textile fabric C is extended on two adjacent sides to provide two overlapping portions D and E, so that when a number of boards are associated as shown in Fig. 2, to form a wall or ceiling surface the extended portions D and E are arranged to overlap the free or clean cut edges of the next adjacent boards and thus provide an overlap which acts as a bond or tie when the finishing coat of plaster is applied.

Fig. 2 illustrates more particularly a wall surface composed of a number of boards secured in position in the usual manner by nails. The board F with the extended fabric portions D and E overlapping the free edges of the next adjacent two boards F and F and covering the nails wherewith they are secured, the extended fabric portions of the board F overlapping the free edges of the adjacent boards and so on. G represents a part finishing coat of plaster which is applied to produce a wall surface which is ca pable of decoration in the known manner.

It will be appreciated that the invention providesa wall board which has sound absorbing or sound insulating characteristics due to the air spaces provided by the corrugations in the base A. Further the wall board provides a surface which offers a considerably greater keying effect than the comparative smooth paper surface hitherto provided. All forms of wall plaster or plastering substances may be applied to such surface and the maximum bonding value is assured even with the cheapest forms of plastering materials available.

A wall board in accordance with the invention is economical to produce, is complete in itself, the base of corrugated cardboard or paper giving increased strength and the textile fabric surface is suitable for finishing, the boards being of a rigid character.

What I claim and desire to secure by Letters Patent is: f

1. A wall board having a base and facing for the reception of an interior finish coating, said board which is exposed when the board is in use, said coating projecting freely beyond a pair of adjacent edges of the base to overlap edges of adjacent boards when erected and thereby cover the heads of the securing nails, said fabric constituting a continuous key over the entire area of the base for the application of a finish coating.

EDGAR ERNEST HARPER. 

